1. Field of the Invention
The present invention relates to a single facer and, more particularly, to a single facer in a corrugating machine for making a single-faced corrugated sheet composed of one corrugated core paper sheet and one liner adhered to the former.
2. Description of the Prior Art
FIG. 1 shows a single facer for use in a corrugating machine of the prior art. A core paper sheet 4 is introduced into a meshing point, at which upper and lower rolls 1 and 2 having their respective corrugated surfaces mesh, so that the sheet is formed into a corrugated shape. Next, the crest portions of the corrugations on one side of the corrugated core paper sheet 4 are made to contact with the surface of a paste application roll 7 so that they are covered with paste. Then, the core paper sheet 4 has its crest portions pressed by a pressure roll 3 and the lower corrugated roll 2 onto a liner 5 fed from another direction until it is worked into a single-faced corrugated sheet 8. The upper corrugated roll 1 is borne rotatably on an arm 9 by means of a bearing. The arm 9 has its one end hinged swingably to a fulcrum frame 11 by means of a pivot pin 10 and its other end hinged through a pin 14 to the piston rod 13a of a pressure cylinder 13. The pressure cylinder 13 is connected to a bracket 12 which is fastened to the frame 11. The lower corrugated roller 2 has its bearing fastened between the frame 11 and the bracket 12. And, the upper corrugated roll 1, the lower corrugated roll 2 and the pressure roll 3 are heated by introducing steam into the inside thereof so as to promote the shaping of the core paper sheet 4 and the adhesion by the paste.
In order to change the height and pitch of the corrugations of the core paper sheet 4 of a corrugated board, it is necessary to replace the upper corrugated roll 1 and the lower corrugated roll 2. In the single facer of the prior art described above, more specifically, pipings or the like for introducing the steam into the bracket 12, the pivot pin 10 and the upper and lower corrugated rolls 1 and 2 have to be disassembled so that the upper and lower rolls 1 and 2 may be replaced. Moreover, the disassembly has to be postponed for one or two days because the upper and lower rolls 1 and 2 and their peripheral devices are cooled down from their hot temperatures during the run of the single spacer.